Canister filter systems with fluid separator filters are used extensively today on equipment such as internal combustion engines, construction and mining machinery, and many other types of industrial machinery. They are used to filter contaminants from fluids in fuel systems, and separate out fluids, such as water, and the like from fuel.
A canister filter system typically includes a base which is often attached to the equipment, a canister (also sometimes called a housing, cup, can, or cover), and a filter which is removably positioned inside the canister. After the filter is positioned inside the canister, the canister is attached to the base with threads or other attachment means to form a sealed compartment around the filter. The canister, base, and filter cooperate to define fluid pathways through which fluid is directed through the filter. The filter contains filter media which traps and collects contaminants as the fluid passes through it and prevents water, or other fluids, from passing through the filter. The trapped contaminants may include dirt, water, soot, ash, metallic particles, and other harmful debris. The water, separated from the fuel, collects in the canister for later draining.
Eventually contaminants clog the filter media and reduce its effectiveness. When this occurs, the filter should be replaced. Typically only the filter needs to be replaced, while the canister, base, and other components are reused. The filter is designed to be conveniently replaced and readily disposed.
Canister filter systems may be provided with a drain. The drain facilitates the removal of fluid that is inside the canister. The drain is typically integrated into the canister.
U.S. Patent Application Publication No. US 2009/078623 A1 to Lauer discloses a filter device including a retaining screw captively secured by a rotary cage extending below a filter housing. The bottom of the cage forms a stop which limits the axial motion of the retaining screw when being screwed out.